Checkmate 032: Nivolumab (N) alone or in combination with ipilimumab (I) for the treatment of recurrent small cell lung cancer (SCLC).

100 Background: Patients (pts) with advanced (adv) SCLC after first-line platinum-based chemotherapy have limited options. Nivolumab, a programmed death-1 (PD-1) immune checkpoint inhibitor, is approved for previously treated metastatic NSCLC in the US and for squamous NSCLC in the EU. Nivolumab + ipilimumab, a cytotoxic T-lymphocyte antigen-4 immune checkpoint inhibitor, has shown durable responses in multiple tumor types. CheckMate 032 was designed to evaluate nivolumab +/- ipilimumab in adv tumors including SCLC. Methods: AdvSCLC pts with progressive disease (PD) after ≥1 platinum-based chemotherapy, regardless of platinum sensitivity or tumor PD-1 ligand 1 (PD-L1) expression, were eligible. Pts received nivolumab ([mg/kg] N3 Q2W) or nivolumab + ipilimumab combination (N1 + I3 or N3 + I1 Q3W for 4 cycles then N3 Q2W). Primary endpoint was objective response rate (ORR). Additional endpoints were safety, overall survival (OS), progression-free survival (PFS), and biomarkers. Results: 180 pts were enrolled (n=80, N3; n=47, N1 + I3; n=53, N3 + I1). Among 127 pts in the N3 and N1 + I3 cohorts, 56% received ≥2 prior regimens and 30% were platinum resistant. Efficacy data are shown (Table). Responses were observed independent of platinum sensitivity and PD-L1 expression. Grade 3–4 treatment-related adverse events (TRAEs) occurred in 11% of pts in N3 and 32% of pts in N1 + I3; 5% and 13% discontinued due to TRAEs, respectively. One TR death due to myasthenia gravis occurred (N1 + I3 arm). Conclusions: Nivolumab and nivolumab + ipilimumab showed durable objective responses and manageable safety profiles, with possibly higher toxicities observed with the combination, in previously treated SCLC pts. Updated efficacy including OS by prior lines of therapy, safety, and biomarkers will be presented for the N3 and N1 + I3 cohorts. Efficacy and safety for the N3 + I1 cohort will be presented. Clinical trial information: NCT01928394. N3a n=80 N1 + I3b n=47 ORR, % (n/N)c 13 (7/55) 31 (14/45) Median DOR, mo Not reached 6.90 Median OS, mo 3.55 7.75 Median PFS, mo 1.38 3.35 1yr OS rate, % 27 48 a15 pts had <6 weeks minimum follow-up bMinimumfollow-up = 120 days c25 pts in N3 and 2 pts in N1 + I3 were non-evaluable for tumor response DOR = duration of response